Carburetor apparatus having an improved fuel metering arrangement

ABSTRACT

A carburetor apparatus having an improved fuel metering arrangement comprises a generally cylindrical housing, a nozzle disposed within the housing and rotatable about an axis coincident with that of said housing, the nozzle being movable along the axis between an upper position and a lower position in response to the flow of air through the housing, a support for rotatably supporting the nozzle, the support including a tubularly-shaped member having an axial passageway formed therein coincident with the axis, a guide for permitting the tubular member to move along the axis with the nozzle and a spring for biasing the tubular member in the direction of the upper position, the tubular member having an inlet to the passageway provided near one end and having the nozzle rotatably affixed to the other end, a valve seat formed along the passageway between said inlet and said other end, a valve needle disposed along the axis and extending into the passageway through the one end, the needle cooperating with the valve seat to form a valve for throttling the flow of fuel through the passageway as the nozzle moves between upper and lower positions, and means affixed to the housing for selectively positioning the valve needle along the axis, the position of the needle along the axis being operative to calibrate the fuel throttling for particular environmental conditions. A pressure regulation system controls the pressure of the fuel entering the inlet, and seals prevent fuel from entering the engine area.

United States Patent De Rugeris [76] Inventor: John De Rugeris, 695 Kenneth Ave.,

Campbell, Calif. 95008 [22] Filed: June 26, 1974 [21] Appl. No.: 483,122

[52] US. Cl 261/39 D; 261/50 A; 261/65;

261/D1G. 74; 55/170; 123/198 DB [51] Int. Cl. F02M 9/08 [58] Field of Search 261/50 A, 39 D, 36 A, 65,

261/DIG. 74; 55/170 [56] References Cited UNITED STATES PATENTS 1,861,694 6/1932 Gindele 261/50 A 2,225,261 12/1940 .lorgensen 261/39 D 2,436,319 2/1948 Meyer 261/65 2,887,309 5/1959 Raynor 261/50 A 2,940,436 6/1960 De Claire, Jr. et al. 261/39 D 3,265,374 8/1966 Morton 261/50 A 3,339,900 9/1967 De Rugeris 261/50 A 3,362,694 l/l968 Gould 261/50 A 3,563,524 2/1971 Jelken 261/50 A 3,618,581 11/1971 Simonet 26l/DIG. 74 3,752,451 8/1973 Kendig 261/50 A Primary ExaminerTim R. Miles Attorney, Agent, or Firm-Thomas E. Schatzel; Claude A. S. Hamrick 7 l "0 illill til/ministe Nov. 18, 1975 [57] ABSTRACT A carburetor apparatus having an improved fuel metering arrangement comprises a generally cylindrical housing, a nozzle disposed within the housing and rotatable about an axis coincident with that of said housing, the nozzle being movable along the axis between an upper position and a lower position in response to the flow of air through the housing, a support for rotatably supporting the nozzle, the support including a tubularly-shaped member having an axial passageway formed therein coincident with the axis, a guide for permitting the tubular member to move along the axis with the nozzle and a spring for biasing the tubular member in the direction of the upper position, the tubular member having an inlet to the passageway provided near one end and having the nozzle rotatably affixed to the other end, a valve seat formed along the passageway between said inlet and said other end, a valve needle disposed along the axis and extending into the passageway through the one end, the needle cooperating with the valve seat to form a valve for throttling the flow of fuel through the passageway as the nozzle moves between upper and lower positions, and means affixed to the housing for selectively positioning the valve needle along the axis, the position of the needle along the axis being operative to calibrate the fuel throttling for particular environmental conditions. A pressure regulation system controls the pressure of the fuel entering the inlet, and seals prevent fuel from entering the engine area.

7 Claims, 4 Drawing Figures Ill! PRESSURE REGULATOR US. Patent Nov. 18, 1975 Sheet3 0f3 3,920,778

CARBURETOR APPARATUS HAVING AN IMPROVED FUEL METERING ARRANGEMENT BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a carburetor for an internal combustion engine and, more particularly, to such a carburetor that employs a selectively positionable valve needle that is operative to calibrate fuel throttling for particular environmental conditions, a fuel pressure regualting system that is responsive to changes in the engine temperature and a split butterfly valve that improves air distribution so as to maintain atomization of the air/fuel mixture that has been created.

2. Description of the Prior Art A carburetor is a device for mixing gasoline with air to form a combustible mixture. Conventional carburetors have six systems. They are the float'system, the cruising or high-speed system, the idle or low-speed system, the accelerator pump system, the power system and the choke system. Functionally, the carburetor mixes the gasoline with air, and then uses this mixture to control the speed and power of the engine. The proportion of fuel and air in the mixture is critical with respect to engine performance.

Conventional carburetors comprise a generally tubular housing through which air is conducted from the outside by the suction strokes of the operating engine pistons. Fuel is drawn by the passing air into the carburetor from a fuel supply line. A pump operated by the engine supplies fuel to the fuel supply line. The flow of air through the carburetor is generally regulated by a circular butterfly valve which is actuated by linkage connected to the vehicle accelerator pedal. The speed of the engine is accelerated when the butterfly valve is opened to admit larger amounts of air, which consequently draws in and mixes with larger amounts of fuel. Acceleration is also dependent upon the load to which the engine is subjected. For example,-when an engine encounters an increased load, the pistons are caused to slow down and consequently decrease the flow of air through the carburetor. Since the same amounts of fuel may be delivered into the carburetor at this time, due to the depression of the accelerator pedal, the explosive mixture established in the carburetor becomes too rich with fuel. Accordingly, engine performance is ad versely affected and, in some instances, the engine may even become flooded. As a result of the problems assov ciated with a conventionalcarburetor of the type described above, the prior art is replete with carburetor arrangements directed to improving the mixing of gasoline and air.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a carburetor which provides an improved distribution and finer atomization of the air/fuel mixture.

It is another object of the invention to provide such a carburetor which controls the fuel dispersed therein with a novel pressure regulating system. 7

It is still another object of the present invention to provide a carburetor which includes a pressure regulating system which is responsive to changes in the'ambient engine temperature.

It is still another object of the present invention to provide, by use of a variable area venturi system, compensation for changes in air density due to a variation in vehicle altitude.

It is still another object of the present invention to provide a safer carburetor in which fuel entering the carburetor is prevented from inadvertently escaping therefrom and entering the hot engine environment.

Briefly, the present invention is directed toward a carburetor apparatus which comprises a generally cylindrical housing, a nozzle disposed within the housing and rotatable about an axis coincident with that of the housing, the nozzle being movable along the axis between an upper position and a lower position in response to the flow of air through the housing, a support forrotatably supporting the nozzle, the support includ- 'ing a tubularly-shaped member having an axial passageway formed therein coincident with the axis, the support includinga gudide for permitting the tubular mem-- bet to move along the axis with the nozzle and a spring for biasing the tubular member in the direction of the An example of such an improved carburetor is that I found in U.S. Pat. No. 3,339,900, entitled Carburetor Arrangement," which issued Sept. 5, 1967, to me. That patent is directed toward a carburetor which has a novel fuel metering and mixing arrangement and which comprises a housing, a fuel supply valve assembly, a fuel dispensing tube slidably mounted with a fuel supply valve assembly, and a fuel distributing nozzle rotatably supported from the tube. The nozzle includes airconducting passages extending from its upper surface to openings located in the peripheral area of the nozzle and fuel distributing channels for distributing fuel from the interior of the tube to discharge orifices located in the peripheral area near the. air outlet openings. The carburetor arrangement operates on engine zone deupper position, the tubular member having an inlet to the passageway provided near one end and having the nozzle rotatably affixed tovthe other end, a valve seat formed along said passageway between said inlet and the other'end, a valve needle disposed along the axis and extending into the passageway through the one end, the needle cooperating with the valve seat to form tively positioning the valve needle along the axis, the position of the needle along the axis being operative to calibrate the fuel throttling for particular environmental conditions. Seals at the top of the tubular member serve to seal in a fuel chamber. In addition, the support includes a breathing hole which allows fuel to escape if the seals should break. A fuel pressure regulating system is responsive to changes in the engine temperature and is operative, in hot and cold environments, to control the pressure of the fuel that enters the inlet. A split butterfly valve covers the bottom opening of the housing to maintain the fuel atomization that has already been achieved, and to allow control of the engine by throttling the flow of air and fuel. When the automobile is accelerated, the downward movement of the fuel nozzle (by engine zone demand) causes the slidable tube in the fuel chamber to maintain the fuel at a cons'tant pressure and volume.

An advantage of the present invention is that it selectively disperses fuel in varying amounts during the hot and cold stages of operation in accordance with temperature variations of the engine.

Another advantage of the present invention is that it prevents fuel from inadvertently escaping from the carburetor into the hot engine environment.

Still another advantage of the present invention is that it provides an improved atomization of fuel by more accurately controlling the distribution of air within the housing by creating a controlled vortex within the housing to direct the atomized air/fuel mixture in a manner that insures maintenance of the fine vapor state.

Other objects and advantages will be apparent to those skilled in the art after having read the following detailed disclosure which makes reference to the several figures of the drawing.

IN THE DRAWING FIG. 1 is a side elevational sectional view of the carburetor of the present invention with the fuel inlet system illustrated diagrammatically.

FIG. 2 is a side elevation view of the adjustable pressure regulating system in accordance with the present invention.

FIG. 3 is a side elevational sectional view of a portion of the carburetor illustrated in FIG. 1.

FIG. 4 is a sectional view taken through the lines 4-4 of FIG. 1 illustrating the split butterfly valve of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, and in particular, to FIG. 1, the carburetor apparatus of the present invention is illustrated. The carburetor comprises an openended, generally cylindrical housing formed by two frusto-conical shells 12 and 14 that are suitably joined along their diverged ends so that the central portion 16 of the enclosure forms a region which is radially expanded relative to its top and bottom portions. Through its open upper neck 18, the housing 10 communicates with the outer atmosphere and enables air to be drawn into the enclosed region. Its bottom neck 20, or opening, leads to the fuel supply manifold of the engine so that the explosive fuel/air mixture formed in the carburetor may be drawn into the cylinders of the engine by the suction strokes of the engine pistons. Supported at the top end of housing 10 in a position coaxially therewith is a fuel supply valve 22, or support, which is arranged to automatically deliver a metered amount of fuel into the fuel distributing nozzle 24 that is rotatably supported below the valve in the upper neck 18 of housing 10. Fuel from the fuel supply line 26 is delivered into fuel chamber 27 through a novel automatically-adjustable fuel pressure regulating system, generally designated by the numeral 28, in a manner that will be subsequently described. A split butterfly valve 30 is arranged in the bottom neck to provide the necessary air/fuel distribution in the housing 10. The valve is selectively opened by the operator of the vehicle and is actuated in any conventional manner, such as by means of an accelerator pedal.

The housing 10 and the fuel distributing nozzle 24, as well as portions of the fuel supply valve 22 and portions of the fuel dispensing tube 32 are similar to those described in detail in U.S. Pat. No. 3,339,900, entitled Carburetor Arrangement, and issued Sept. 5, 1967, to me, and that patent is incorporated by reference as part of the specification of this invention for details of construction for similar components. It should be recognized that this invention provides several novel features not disclosed in my earlier patent.

With reference to FIG. 3, the fuel supply valve comprises an outer enclosure which includes a cover 31 and a cylindrically-shaped side wall 32 which depends from the cover 31 so as to define the cylindrically-shaped fuel chamber 27 therewithin. A breathing hole 66 which is in the form of an apertured passageway extends from an inlet on the inner surface of the cover to an outlet in the upper neck of the housing. An aperture 48 extends through the side wall 32 and serves as an inlet for receiving fuel from the supply line 26 through an interconnecting passageway. As shown, the passageway extends angularly through the housing and a bridge portion secured thereabove. Thus, the supply line does not interfere with the seating of an air cleaner assembly (not shown) on the carburetor. A bottom plate 33 is secured to the bottom surface of the side wall 32 by screws 34. A collar 36 extends diagonally across the open uppe neck 18 of the housing and is bolted to the upper edge of the neck at diagonally opposite points thereof by screws 37. Set screws 39 extend through respective apertures in the collar 36 so as to secure the fuel supply valve 22 to the collar. The bottom plate 33 includes a centrally-located circular aperture for slidably receiving and guiding an elongated fuel dispensing tube 50. The tube 50 is coaxial with the fuel supply valve 22 and the housing. Secured to the periphery of the aperture in the plate 33 is an annular elastomeric sealing washer 38. The upper end of the dispensing tube 50 is provided with an outwardly-directed annular flange 40 which extends toward the side walls 32. Coiled around the tube is a spring 42 which is compressed between spring retaining elements 43 and 44. The spring 42 biases the fuel dispensing tube 50 upwardly in an elevated position or upper position against the cover 31. Secured between the upper flange 40 and the upper spring retaining element 43 is a seal 45 which serves to seal the fuel within the fuel chamber 27. Similarly, a seal 46 is secured between the lower spring retaining element 44, and the bottom plate 33 preventing fuel from leaking along the tube 50 into the housing 10. The interior of the fuel dispensing tube is hollow and includes an upper fuel receiving cavity 51 and a more narrow apertured passageway 52. A pair of inlets, or apertures, 49 provide a conduit for fuel to flow from the chamber 27 to the cavity 51. The passageway 52 has an axis that is coincident with that through the housing and conducts fuel to the fuel distributing noz-.

zle 24. A jet 47, or valve seat, is detachably held within the fuel dispensing tube 50 at the boundary of the cavity 51 and the passageway 52, and cooperates with the needle to form a valve for throttling the flow of fuel through the passageway. The amount of fuel which flows to the nozzle 24 is dependent upon the depression of the tube 50 from its elevated position as will be subsequently described.

In accordance with one feature of the present invention, a needle valve 54 is adjustably mounted through a central coaxial threaded aperture in the cover 31. The valve 54 comprises a cap, or upper mounting portion, 56 that is externally threaded and a valve needle, or control rod portion, 58 which is tapered downwardly to a needle point at its distal end. The length of the valve is such that the tapered control rod 58 always extends through the cavity 51 into the passageway for all depressed positions of the fuel dispensing tube 50. As the tube 50 slides aalong the side wall 32, different annular areas of the passageway 52 are exposed between the outer periphery of the control rod 58 and the concentric inner periphery of the jet 46. A central seal 62 disposed internally of the dispensing tube 50 against a shoulder therewithin forms an upper wall of the cavity 51. The seal 62 is formed from an elastomeric material and has an annular opening therethrough. The periphery of the inner opening resiliently and intimately engages the outer periphery of the control rod 58 as it slides therethrough and serves to prevent fuel within the cavity from escaping upwardly along the control rod. A threaded screw 64 secures the seal 62 in position over the cavity 51.

Accordingly, fuel entering the fuel chamber 27 is maintained therein by the seals 45, 46 and 62, and thus prevented from escaping into the cylindrical recess under the cover 31. However, if the seals should break or deteriorate with the passage of time, an additional safety factor has been included in this carburetor. In particular, the breathing hole 66 allows fuel to escape, and also serves to relieve the pressure which builds up as the slidable tube moves up and down within the fuel supply valve assembly. Because of the seals and the.

breathing hole, fuel entering the carburetor is unable to leak onto the engine. Thus, the possibility of engine fires is precluded from occurring.

Referring still to FIG. 3, the fuel and air distributing nozzle 24 is rotatably supported from the bottom end of the fuel dispensing tube 50 by a ball bearing assembly 80. The nozzle is disclosed in the cited patent and reference is made to that patent for details of construction not provided herein. As described, the nozzle has a conical shape and is selectively positionable in the upper portion of the housing 10. The top surface includes a wreath of air conducting passages 70 which are arranged concentrically around the nozzle and extend from equi-shaped air intake openings in the top surface in a direction tangentially of an imaginary circle, that is concentric with and of a smaller diameter than the nozzle, outwardly to equi-shaped outlets located in the peripheral area of the nozzle.

The ball bearing assembly includes an inner race 74, which is carried by the fuel dispensing tube 50, an outer race, and a plurality of balls carried in the circular passageway between the races. The outer race of the ball bearing is held in place by a plate 78 which forms the upper surface of the nozzle. Since the bearing assembly is not sealed, the air flowing through the nozzle serves to self-lubricate the bearing assembly. A fuel distributing chamber 84 communicates with the fuel passageway 52 that is formed in the nozzle. Thin fuel supply channels (not shown) radiate from a fuel distributing chamber in a manner of the spokes of a wheel toward the outlet openings and terminate on the peripheral area of the nozzle in minute orifices 88 respectively adjacent to a corresponding air outlet opening.

Still another feature of the present invention is the novel pressure regulating system 28 which automatically regulates the pressure of the fuel which enters the fuel chamber 27. Referring now to FIG. 2, the pressure regulating system comprises a fuel shut-off valve 90, an automatically adjustable pressure regulator valve 92 and a vapor relief valve 94 which are serially connected between the fuel inlet 96 and the inlet aperture 48.

The shut-off valve is responsive to the on or off state of the ignition and is operative to prevent fuel from entering the pressure regulator valve 92 when the ignition is turned off. Accordingly, it serves to prevent bleeding the fuel from the fuel line into the carburetor.

The pressure regulator valve 92 includes an inlet 100, an outlet 102, and a control valve 104. The control valve 104 includes a threaded aperture 106 which receives the threaded shaft of screw 108. The screw 108 provides a static control on the opening of the pressure regulator, and consequently the pressure of the fuel flowing through the pressure regulator valve 92. In order to provide a dynamic control on the pressure of the fuel, a novel dynamic pressure assembly, generally illustrated by the numeral 1 10, is provided. The assembly 1 10 includes a thermal-mechanical transducer 1 12, which is preferably a bi-metallic coil spring, that is linked by a lever rod 114 to dynamically control the adjustment of the screw 108. The coil spring operatively expands or contracts in length in accordance with engine temperature. The base of the coil spring 112 is mounted within the engine, preferably to the manifold, by screw 120.

In operation, the static fuel flow is adjusted with screw 108 so as to provide optimum engine performance with respect to the pressure in which the vehicle is to be operated. In making this setting, consideration should be-given to the altitude and the season of the year to compensate for the ambient pressure and temperature. Thereafter, screw 116 is tightened against the lever 114 to lock the screw 108 into its static position. Consequently, any change in the setting of the screw 108 is due to changes in the dynamic tempereature of the engine. For example, as the engine temperature increases, the spring 112 expands outwardly, thereby causing the screw 108 to rotate counterclockwise. Similarly, a temperature decrease causes the screw to rotate in the opposite direction. Thus, the pressure regulator valve 92 is dynamically adjusted in response to engine temperature.

The pressure relief valve 94, also referred to asth anti-vapor lock valve, serves to release any air trapped in the fuel inlet system. The valve comprises a fuel chamber 122 which is interconnected between the inlet 124 and the outlet 26. Disposed within the fuel chamber is a substantially cylindrical structure which includes a plurality of walls 126 separated by adjacent slots. The bottom and top surfaces of the cylindrical structure are open so as to respectively communicate with the fuel line and the outside environment. The respective ends of the walls are curved inwardly at the top and bottom portions so as to secure therewithin a ball 128. The ball 128 has a diameter which is slightly less than the diameter of the walls. In operation, as fuel flows through the valve 94, the ball is forced upwardly so as to close the top opening such that fuel flowing through the valve 94 cannot escape. If, however, air becomes trapped in the fuel line and thus flows into the chamber 122, the pressure forcing the ball against the top opening decreases and the ball drops. As the ball drops, it assumes a position intermediate the top and bottom openings or becomes seated on the bottom surface as illustrated in phantom at 129. In this instance, the trapped air flows out of the top opening into the ambient surroundings, or into a tubular passage to re turn the fuel-laden air to a fuel tank mounted in the vehicle. As soon as the air is released, the chamber again fills with fuel and normal operation continues. Preferably, this pressure relief valve should be included on all cars that do not have a fuel by-pass system as standard equipment.

As a result of the novel pressure regulation system 28 in the fuel supply line, the pressure and the amount of the fuel entering the fuel chamber 27 is accurately and automatically controlled to provide the optimum fuellair ratio for variations in the ambient engine temperature. Preferably, the fuel shut-off valve, the pressure regulator valve, and the pressure relief valve which comprise the pressure regulation system are of the type that are commercially available.

Referring to FIG. 4, the split butterfly valve feature of the present invention is illustrated. As shown therein, the split butterfly valve 30 is disposed at the bottom neck 20 of the housing so as to cover the bottom opening thereof. The valve includes a central support 132 which extends diametrically across the base. Two rotatable shafts 136 and 138 are disposed on opposite sides of the support in a direction parallel thereto and are coupled together by a crank 140. Two semicircularly-shaped covers 142 and 143 are secured to the respective shafts by screws 144. A linkage 146 couples the shaft 136 to an appropriate throttle control, such as the accelerator pedal. A stop 148 limits the rotation of the shaft.

Accordingly, as the accelerator pedal is depressed, the linkage 146 rotates 136, which, through crank 140, also causes shaft 138 to rotate. Rotation of the shafts cause the coverings to move between a closed position, in which they extend between the support and the housing, to an open position in which they are angularly disposed. The angular disposition of the coverings allows a controlled amount of air to flow into and through the housing. As a result of the split semicircular coverings, four discrete airpaths are provided as at 150, 151, 152 and 153, for the air which is drawn through the top opening 18. Since two of the openings are disposed in the central portion of the valve, an even distribution of the air/fuel mixture is provided within the interior of the housing, thereby maintaining the atomization of the fuel.

In operation, prior to the opening of the butterfly valve 30, the spring 42 maintains the fuel dispensing tube 50 in its upper position. Generally in this position the jet is fully, or substantially, covered by the tapered control rod 58. As a result, no (or very little) fuel can flow to the fuel distributing chamber of the nozzle. Upon actuation of the ignition system and the depression of the accelerator pedal, the fuel shut-off valve is actuated, and the split butterfly valve 30 is selectively opened. As soon as the opening of the butterfly valve 30 permits, the engine pistons draw air through the housing 10. The in-rushing air impacts the top surface of the nozzle and causes the nozzle and, consequently, the fuel dispensing tube 50 to become depressed and rotate.

Since the needle valve 54 is adjustably secured to the cover 31 of the fuel supply valve, the downward sliding movement of the fuel dispensing tube causes the jet to be moved along the tapered control rod 58. Thus, the concentric aperture in the jet is opened by varying degrees depending upon the amount of air drawn against the top surface of the nozzle by the suction strokes of the engine pistons. By appropriately turning the needle valve 54, the initial position of the control rod relative to the jet 46, commonly referred to as the idle, is set. Because of the novel construction of this carburetor, this adjustment is accessible externally of the carburetor and can be easily made to accommodate the ambient conditions, such as altitude and temperature, which are anticipated. Once the adjustment is made, controlled quantities of fuel are dispensed from the cavity 3 51 through the passageway 52 and released through the orifices in the nozzle toward the walls of the housing 10.

Since the impacting air is guided from the top surface of the nozzle through the air conducting passages and into the interior of the housing adjacent the streams of fuel, the currents of air entrain the streams of the fuel and form many downwardly slanted, tangentially-directed jets of air and fuel. The air that passes through the air conducting passages of the nozzle causes the nozzle to spin rotationally. The intersection of this air and the fuel causes the fuel to be broken up as in an aerosol generator. The air moving over the surface of the noule meets the fuel/air spray so as to bend it away from the walls and also to create a cushion of air against the walls. This cushion prevents the fuel from impacting the walls and allows it to maintain its fine mist form. The vortex created in this manner allows this mixture to enter the manifold via the split butterfly. Thus, each cylinder receives the same mixture of air and fuel whereby cylinder-to-cylinder and cycle-tocycle variations are reduced.

From the above, it can be seen that an improved carburetor has been described which provides an optimum combustion mixture for all engine temperatures and establishes a smooth and uniform performance of the engine, and which fulfills all of the objects and advantages set forth above.

While there has been described what is at present considered to be the preferred embodiment of the invention, it will be understood that various modifications may be made therein, and it is intended to cover in the appended claims all such modifications as fall within the true spirit and scope of the invention.

What is claimed is:

1. A carburetor apparatus comprising:

a generally cylindrical housing including a bottom opening and a split butterfly valve which covers said bottom opening, said split butterfly valve including a central support extending diametrically across said bottom opening, two rotatable shafts, which extend substantially parallel to said central support on opposite sides thereof, two semicircularly-shaped covering portions which are secured to said respective shafts, crank means connected to said shafts for coupling the rotation of said shafts together, and throttle means coupled to one of said shafts and operative to selectively rotate said one shaft from a closed position, wherein said semicircular coverings are disposed across said bottom opening to an open position, wherein said semicircular coverings are only partially disposed across said bottom opening so as to define two central openings and two circumferential openings;

a nozzle disposed within said housing and rotatable about an axis coincident with that of said housing, said nozzle being movable along said axis between an upper position and a lower position in response to the flow of air through said housing;

support means for rotatably supporting said nozzle, said support means including a tubularly-shaped member having an axial passageway formed therein coincident with said axis, said support means including guide means for permitting said tubular member to move along said axis with said nozzle and means for biasing said tubular member in the direction of said upper position, said tubular member having an inlet to said-passageway pro-v vided near one end and having said nozzle rotatably affixed to said other end;

means disposed along said passageway between said inlet and said other end forming a valve seat;

a valve needle disposed along said axis and extending into said passageway through said one end, said needle cooperating with said valve seat to form a valve for throttling the flow of fuel through said passageway as said nozzle moves between said upper and lower positions; and

means affixed to said housing for selectively positioning said valve needle along said axis, the position of said needle along said axis being operative to calibrate the fuel throttling for particular environmental conditions and said central and circumferential openings providing a more even distribution of the maintain atomization of the fuel.

2. A carburetor apparatus as recited in claim 13 including means for automatically regulating the pressure of the fuel which enters said inlet.

3. A carburetor apparatus as recited in claim 2 wherein said automatic pressure regulating means comprises an adjustable pressure regulator valve and means responsive to changes in ambient engine conditions and operative to selectively adjust said pressure regulator valve, thereby to control the pressure of the fuel.

4. A carburetor apparatus as recited in claim 3 and further comprising a fuel shut-off valve responsive to the condition of the ignition and operative to prevent fuel from entering said pressure regulator valve when said ignition is turned off.

5. A carburetor apparatus as recited in claim 3 and further comprising a vapor relief valve coupled between said pressure regulator valve and said inlet for releasing air that may become trapped therein thereby 20 'to prevent vapor locks.

6. A carburetor apparatus as recited in claim 3 wherein said means responsive to changes comprises a temperature responsive thermostat.

7. A carburetor apparatus as recited wherein said pressure regulator valve includes a control valve comprising a rotatable shaft, and wherein said thermostat comprises a bimetallic coil spring having a length that varies as a function of temperature, and link means coupled between said coil spring and said rotatable shaft and operative to rotate said shaft as the length of said coil spring changes.

in claim 6 

1. A CARBURETOR APPARATUS COMPRISING: A GENERALLY CYLINDRICAL HOUSING INCLUDING A BOTTOM OPENING AND A SPLIT BUTTERFLY VALVE WHICH COVERS SAID BOTTOM OPENING, SAID SPLIT BUTTERFLY VALVE INCLUDING A CENTRAL SUPPORT EXTENDING DIAMETRICALLY ACROSS SAID BOTTOM OPENING, TEO ROTATABLE SHAFTS, WHICH EXTEND SUBSTANTIALLY PARALLEL TO SAID CENTRAL SUPPORT ON OPPOSITE SIDE THEREOF, TWO SEMICIRCULARLY-SHAPED CONVERING PORTIONS WHICH ARE SECURED TO SAID RESPECTIVE SHAFTS, CRANK MEANS CONNECTED TO SAID SHAFTS FOR COUPLING THE ROTATION OF SAID SHAFTS TOGETHER AND THROTTLE MEANS COUPLED TO ONE OF SAID SHAFTS AND OPERATIVE TO SELECTIVELY ROTATE SAID ONE SHAFT FROM A CLOSED POSITION, WHEREIN SAID SEMICIRCULAR COVERINGS ARE DISPOSED ACROSS SAID BOTTOM OPENING TO AN OPEN POSITION, WHEREIN SAID SEMICIRCULAR COVERING ARE ONLY PARTIALLY DISPOSED ACROSS SAID BOTTOM OPENING SO AS TO DEFINE TWO CENTRAL OPENINGS AND TWO CIRCUMFERENTIAL OPENINGS; A NOZZLE DISPOSED WITHIN SAID HOUSING AND ROTATABLE ABOUT AN ASIX COINCIDENT WITH THAT OF SAID HOUSING, SAID NOZZLE BEING MOVABLE ALONG SAID AXIS BETWEEN AN UPPER POSITION AND A LOWER POSITON IN RESPONSE TO THE FLOW OF AIR THROUGH SAID HOUSING; SUPPORT MEANS FOR ROTATABLY SUPPORTING SAID NOZZLE, SAID SUPPORT MEANS INCLUDING A TUBULARLY-SHAPED MEMBER HAVING AN AXIAL PASSAGEWAY FORMED THEREIN COINCIDENT WITH SAID AXIS, SAID PASSAGEWAY FORMED THEREIN COINCIDENT FOR PERMITTING SAID TUBULAR MEMBER TO MOVE ALONG SAID AXIS WITH SAID NOZZLE AND MEANS FOR BIASING SAID TUBULAR MEMBER IN THE DIRECTION OF SAID UPPER POSITION, SAID TUBULAR LAR MEMBER HAVING AN INLET TO SAID NOZZLE ROTATABLY AFFIXED TO NEAR ONE END AND HAVING SAID NOZZLE ROTATABLY AFFIXED TO SAID OTHER END; MEANS DISPOSED ALONG SAID PASSAGEWAY BETWEEN SAID INLET AND SAID OTHER END FORMING A VALVE SEAT; A VALVE NEEDLE DISPOSED ALONG SAID AXIS AND EXTENDING INTO SAID PASSAGEWAY THROUGH SAID ONE END, SAID NEEDLE COOPERATING WITH SAID VALVE SEAT TO FORM A VALVE FOR THROTTLING THE FLOW OF FUEL THROUGH SAID PASSAGEWAY AS SAID NOZZLE MOVES BETWEEN SAID UPPER AND LOWER POSITIONS; AND MEANS AFFIXED TO SAID HOUSING FOR SELECTIVELY POSITIONING SAID VALVE NEEDLE ALONG SAID AXIS, THE POSITION OF SAID NEEDLE ALONG SAID AXIS BEING OPERATIVE TO CALIBRATE THE FUEL THROTTLING FOR PARTICULAR ENVIRONMENTAL CONDITIONS AND SAID CENTRAL AND CIRCUMFERENTIAL OPENINGS PROVIDING A MORE EVEN DISTRIBUTION OF THE BLEND OF AIR AND FUEL WITHIN THE HOUSING, THEREBY TO MAINTAIN ATOMIZATION OF THE FUEL.
 2. A carburetor apparatus as recited in claim 13 including means for automatically regulating the pressure of the fuel which enters said inlet.
 3. A carburetor apparatus as recited in claim 2 wherein said automatic pressure regulating means comprises an adjustable pressure regulator valve and means responsive to chaNges in ambient engine conditions and operative to selectively adjust said pressure regulator valve, thereby to control the pressure of the fuel.
 4. A carburetor apparatus as recited in claim 3 and further comprising a fuel shut-off valve responsive to the condition of the ignition and operative to prevent fuel from entering said pressure regulator valve when said ignition is turned off.
 5. A carburetor apparatus as recited in claim 3 and further comprising a vapor relief valve coupled between said pressure regulator valve and said inlet for releasing air that may become trapped therein thereby to prevent vapor locks.
 6. A carburetor apparatus as recited in claim 3 wherein said means responsive to changes comprises a temperature responsive thermostat.
 7. A carburetor apparatus as recited in claim 6 wherein said pressure regulator valve includes a control valve comprising a rotatable shaft, and wherein said thermostat comprises a bimetallic coil spring having a length that varies as a function of temperature, and link means coupled between said coil spring and said rotatable shaft and operative to rotate said shaft as the length of said coil spring changes. 